Search results for "TRANSMISSION ELECTRON"
showing 10 items of 426 documents
Hydrogen peroxide sensors for cellular imaging based on horse radish peroxidase reconstituted on polymer-functionalized TiO2 nanorods
2011
We describe the reconstitution of apo-horse radish peroxidase (apo-HRP) onto TiO2 nanorods functionalized with a multifunctional polymer. After functionalization, the horse radish peroxidase (HRP) functionalized TiO2 nanorods were well dispersible in aqueous solution, catalytically active and biocompatible, and they could be used to quantify and image H2O2 which is a harmful secondary product of cellular metabolism. The shape, size and structure of TiO2 nanorods (anatase) were analyzed by transmission electron microscopy (TEM), high resolution TEM (HRTEM), electron diffraction (ED) and X-ray diffraction (XRD). The surface functionalization, HRP reconstitution and catalytic activity were con…
Studies of the Ca4Mn3O10structure obtained using high pressure and high temperature
2002
An ideal n = 3 member of the group of Ruddlesden?Popper (RP) phases Ca4Mn3O10 was obtained by solid-state reaction under high pressure. This phase has been studied by transmission electron microscopy, convergent beam electron microscopy, high-resolution transmission electron microscopy, and parallel electron energy-loss spectroscopy. The lattice parameters are derived as a = b = 0.37 nm and c = 2.69 nm with the space group I4/mmm, which is the space group of the ideal RP phase.
Morphological transformations in a dually thermoresponsive coil-rod-coil bioconjugate.
2013
We report the conformational and assembly behavior of a thermoresponsive triblock biohybrid conjugate under aqueous conditions. The triblock comprises of poly(diethylene glycol methyl ether methacrylate) (PDEGMEMA) conjugated to the ends of a triple-helix forming collagen-like peptide. The circular dichroism (CD) experiment confirms the ability of the collagen-like peptide middle block to assemble as a triple helix in the hybrid conjugate. Above the LCST (∼35 °C), the collapse of the thermoresponsive PDEGMEMA polymer at the ends of the peptide domain resulted in a concomitant increase in the conformational stability of the peptide domain towards thermal denaturation. Upon cooling back, the …
Melt processing of hexa-peri-hexabenzocoronene on the water surface
2011
A discotic polycyclic aromatic hydrocarbon, hexa-peri-hexabenzocoronene, was oriented by slow cooling from the isotropic phase on a water surface as a film. For melt processing at low temperatures, an HBC derivative with long swallow-tailed alkyl side chains was chosen. The supramolecular organization in the resulting thin layer was investigated by electron microscopy. In high-resolution mode, the structural study showed large domains in which the columnar structures were oriented uniaxially with an edge-on arrangement of the hydrophobic molecules. The length of the stacks exceeded several hundred nanometers without obvious defects. The small-area analysis by TEM allowed the direct visualiz…
Imidazolium functionalized carbon nanotubes for the synthesis of cyclic carbonates: reducing the gap between homogeneous and heterogeneous catalysis
2016
Single walled carbon nanotubes (SWCNTs) were functionalized with imidazolium salts bearing vinyl functionalities. An extremely high loading of active species was achieved through a straightforward one-pot procedure involving self-assembly of the imidazolium moieties followed by radical initiated polymerization of the double bonds. The materials were extensively characterized by transmission electron microscopy, Raman spectroscopy, nitrogen physisorption and combustion chemical analysis. The imidazolium functionalized SWCNTs displayed excellent catalytic activity for the reaction of CO2 and epoxides to produce cyclic carbonates as demonstrated by the excellent turnover numbers (TON). Moreove…
Organometallic ABC-triblock copolymers
1998
The interaction of Fe and Pd complexes with double bonds of the polybutadiene (PB) block in polystyrene-polybutadiene-poly(methyl methacrylate) block copolymers has been studied. The incorporation of Fe(CO)3 fragments into the PB bloc was found to result in an increase in its rigidity. The presence of iron or palladium complexes in the PB block affects strongly the morphology of the triblock copolymers.
Multifunctional polymer-derivatized γ-Fe2O3 nanocrystals as a methodology for the biomagnetic separation of recombinant His-tagged proteins
2008
Abstract Multifunctional polymer-derivatized superparamagnetic iron oxide (γ-Fe2O3) nanoparticles were prepared for biomagnetic separation of histidine-tagged recombinant proteins building up a faster and efficient method for protein separation by making use of their intrinsic magnetic properties. Using polymer bound γ-Fe2O3 nanocrystals, a 6× histidine-tagged recombinant protein (silicatein) with a molecular weight of 24 kDa has been isolated and purified. The supermagnetic iron oxide nanocrystals were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), SQUID and Mossbauer and the polymer functionalization of the γ-Fe2O3 nanocrystals was monitored by UV–vi…
Progress in polymeric material for hydrogen storage application in middle conditions
2014
Hydrogen sorption using a manganese oxide anchored to PEEK (Poly(ether-ether-keton)) matrix was studied. The functionalization process and the obtained results on hydrogen storage capability of the synthesized polymer are reported. The functionalised polymer was characterised by Scanning Electron Microscopy, Transmission Electron Microscopy, X-ray diffraction and Volumetric Hydrogen sorption measurements. Different synthesis conditions in terms of precursor concentration and reaction time were used and the direct correlation between manganese oxide percentage and hydrogen storage capability was confirmed. In this way different powders were synthesised. It is assumed that the sample with 78 …
Growth of fibrous aggregates of silica nanoparticles: Fibre growth by mimicking the biogenic silica patterning processes
2009
We describe the self-assembly of discrete SiO2 nanofibers via grafting of silicatein side chains to a polymer backbone. The covalent binding of silicatein to the backbone of the polymer is based on the affinity of the nitrilotriacetic acid (NTA) side chain, which serves as a ligand for the immobilization of His-tagged silicatein. The surface charge and the bulkiness of the protein moieties prevent the entropically favoured coil formation of the polymer and force it to adopt an open chain structure after hydrolysis of the silica precursors. The probes were characterized by scanning force microscopy (SFM) and optical light microscopy. Surface complexation of the resulting silica nanoparticles…
Enzyme-Mediated Deposition of a TiO2Coating onto Biofunctionalized WS2 Chalcogenide Nanotubes
2009
A chemically specific and facile method for the biofunctionalization of WS2 nanotubes (NT-WS2) is reported. The covalent modification strategy is based on the affinity of the nitrilotriacetic acid (NTA) side chain, which serves as a ligand for the surface binding to NT-WS2 and simultaneously as an anchor group for the binding of His-tagged proteins to the polymer backbone. The polymer functionalized WS2 nanotubes can be solubilized either in water or organic solvents; they are stable for at least one week. The probes were characterized by FT-IR and UV-vis spectroscopy. The immobilization of silicatein, a hydrolytic protein encountered in marine sponges, was visualized by scanning force micr…